In 2019, the United Nations General Assembly and UNESCO proclaimed the International Year of the Periodic Table of Chemical Elements, marking the 150th anniversary (6 March 1869) of Vladimir Mendeleev’s presentation of the first Periodic Table.
We have all studied the Periodic Table, yet we are often unaware of the specific characteristics, history and uses of individual elements. However, it is precisely these uses, in particular, that change over time as we learn more about their dangers, limitations or capabilities.
Element 118, oganesson, for example, is the most recently discovered element on the Periodic Table. It was discovered in 2002 and is named after Yuri Oganessian, the living Russian-Armenian physicist considered the world’s leading researcher when it comes to creating superheavy elements. Oganesson is in fact the heaviest element in the Periodic Table, although several scientists are working towards creating even heavier elements. Element 119 is in the pipeline, although its creation is still a long way off.
Precisely because of its mass, scientists have assumed that the electrons of oganesson lose their usual shell structure.
Oganesson is a very unusual element: whilst its position in the noble gas group on the Periodic Table would suggest it is a gas at room temperature and not very reactive, computational calculations indicate that it behaves like a metallic semiconductor – a property certainly not typical of noble gases. This is a characteristic that in some ways calls into question the intrinsic nature of the Periodic Table: in the past, chemists predicted the properties of as yet unknown elements by using knowledge of known elements, which are arranged precisely according to the periodicity of their properties. Oganesson throws a spanner in the works and robs the Periodic Table of its predictive power.
Only a few atoms of oganesson have been produced, and their isotopes have very short half-lives; however, it is assumed that there exists what scientists call an ‘island of stability’ for the isotopes of certain superheavy elements: that is to say, as they have longer half-lives, they can be studied in greater depth.
At present, with the discovery of oganesson, the Periodic Table appears to be complete, with all seven periods filled.
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